1, the exhaust fan should look smooth, no scratches and bumps processing defects, coating evenly. Under normal circumstances we use low-noise exhaust fan HTF fire, and use muffler noise, acoustic and other measures to reduce noise transmission. When the fan operating conditions change, adjust the speed does not increase the use of pipe resistance does not increase the fan flow field instability and unevenness exhaust fan manufacturers, reasonable steps roof exhaust fan to reduce fan noise factors increase, can effectively reduce the noise. Two-speed exhaust fan fire power introduced by the regional driving force for me, the power box design drawings must be dual power, but automatically force me to the middle of the fan should have a fan control box, the fan control box drawing manufacturers are generally marked supporting, so the fan control box can not double the power of large exhaust fan, but also cost savings, fire inspection no problem. The so-called two-speed fan is asynchronous Luliang exhaust fan, exhaust fan factory, Shenglong air conditioning (certified merchants) are provided by the Texas Shenglong ventilation and air conditioning plant. Texas Shenglong ventilation and air conditioning plant (www.fengguan666.com) (www.dzsltfkt.com) is specialized in "plate exhaust port, exhaust air box, high-temperature exhaust fan fire" of the enterprise, the company adhering to the "integrity management, hard service "concept, to provide you with the highest quality products and services. Welcome to inquire! Contact: Hou Jingli.